James River, a river of Virginia. It is formed by the junction of the Jackson and Cowpasture rivers in the Allegheny Mountains, and flows about 340 miles (550 km) in a generally eastward course into Chesapeake Bay at Hampton Roads. The lower part of the river forms a broad and deep estuary navigable by oceangoing ships. Ships of lighter draft go as far upstream as Richmond. Jamestown colony was founded near the mouth of the river in 1607.